A day on the Farnes

I spent Saturday on the Farne Islands with a friend and his father, who was visiting the UK from abroad. They had asked to see some UK birdlife and I reasoned that our breeding seabirds are one of this country’s most spectacular wildlife sights. Although cold overnight (3 degrees in May!), the cloud quickly dispersed and for most of the day we had sunshine and blue skies – which also means blue seas in our photographs, a real bonus.  

We travelled up to Northumberland on Friday, to a small town at the foot of the Cheviot Hills. I was delighted to find a breeding pair of Dipper under a bridge close to our house. Dawn on Saturday found us by the river, watching the comings and goings of thse fabulous birds:

Then, after breakfast, we drove to Seahouses to catch the boat to the Farne Islands.

Immediately there were birds and wildlife. This smart drake Eider was one of a small number in the harbour:

As we left the harbour, a series of distant splashes drew our attention to a distant pod of Bottlenose Dolphin in the bay:

As we approached the Farnes, the sheer number of seabirds around the islands became apparent:

There were vast numbers of Guillemots, smaller numbers of Puffins and Razorbills, with Kittiwakes circling above and Shags jump-diving for fish. A few of the Guillemots were of the bridled form, with smart white eyewear:

But it was always the Puffins that caught the eye. Seeing these birds close on the water in sunshine was a real treat:

We landed on Staple Island, where one can walk just a few meters from thousands of breeding seabirds. Shags were nest building and incubating all around us:

Razorbills were breeding too, but not in the same vast numbers as the Guillemots:

I have visited the Farnes before, in July 2011. It was fascinating to see the different behaviour of the birds at this time of  year, at a much earlier date in the breeding season. There were no birds bringing in fish, as no young had been hatched yet. Instead the Puffins were in courtship and burrow-claiming mode. Some birds had obviously been underground recently:

Whilst others ran around with beaks full of nesting material:

We saw a wide variety of social interactions between the Puffins. The bird below was actively defending a burrow entrance. Bill-gaping is antagonistic behaviour, revealing the birds bright yellow gape and tongue:

The left-hand bird of this pair approached the right-hand bird with a low-profile-walking display, before they began bowing to each other:

Then it was time for some portraits:

Getting flight pictures of Puffin takes some time, they are fast fliers. I eventually found a spot where I could look down on approaching Puffins, where the light was good and the sea appeared blue:

We left Staple Island at lunchtime and took the boat to Inner Farne.

This larger island has the breeding auks of Staple Island, but also many breeding terns, including Arctic, Common and Sandwhich Terns.  The Arctic Terns here are ridiculously tame:

This early in the season we saw little aggressive behaviour from the the Arctic Terns. In July one needed head protection to avoid birds diving at visitors on the walkways. 

The cliffs also held breeding Guillemots, plus a small number of bridled birds, my favourite form:

But even on Inner Farne, Puffins were everywhere. The numbers were astounding. They sat on open grassy areas, on buildings, on walls…

… even flying directly overhead:

The day finished, as it had begun, with a nice drake Eider:

We left the Arctic Terns and breeding seabirds and sailed back to Seahouses:

Visiting the Farne Islands in the breeding season is an almost overwhelming experience. The sheer number of breeding birds is a powerful assult on one’s senses, both sight and smell! But being surrounded by thousands of Puffins makes the day a very special encounter.

Emperors emerging

Great excitement yesterday as our first Emperor Moth emerged. They are stunning moths, quite large, with obvious “eye” patches on both fore and hindwings, above and below. This fabulous female was one of a batch we raised on Hawthorn last summer:

Emperor Moths, from egg to cocoon in 6 weeks

Detail of the eye pattern on the upper forewing:

Even from below, the “eyes” on the wings are visible. These presumably act as a deterrent, confusing potential predators into thinking that they are looking into the face of a much larger animal:

We transferred our Empress to a hawthorn bush across the road, one of the Emperor Moth’s host plants. It was the same bush that we fed the caterpillars from last summer.  We left her there and thought that was it.

This afternoon, my wife took our children and some friends across the road to see if the female Emperor had moved. She had not. But even better, she had attracted not one, but two, males:

Male Emperor Moths are smaller and more reddish than the large silver females. One male had succeeded in attaching his abdomen to the female. This was a rather worn individual, with evidence of some wing damage in comparison with the completely pristine, freshly emerged female:

The male Emperors had located our female purely by scent. Their antennae are finely tuned to the pheromones that the female emits from her abdomen. I wrote about the wonder and sensitivity of moth antennae in this recent post:

The wonder of antennae

In over two years of regular moth trapping in Headington we have never caught an Emperor Moth. This was no great surprise, they are not easily attracted to light. Instead, the males spend their time seeking out females, tracking them down efficiently by following their pheromone trail. In less than 24 hours, our female had attracted two males, demonstrating the species is present in our local area. The male’s antennae are clearly visible here:

Below, underwing details. The clasping mechanism at the end of the abdomen is visible. Each species of moth has evolved only to interlock with females of the same species. 

Below upperwing detail of the, slightly tatty, male Emperor:

A fantastic afternoon, with excitement for adults and children alike, present in the company of the Emperors. 

Blenheim Bonaparte’s

Bonaparte’s Gulls don’t create the stir they once did. The bird at Farmoor in mid-May 2000 was a major event. Since then there have been another four, all in spring, with birds being found on 18th April 2006; 1st May 2007; 11th April 2009; 8th April 2017. The bird found yesterday by Nic Hallam (who has found most of the county records) is the 6th for the county, by my reckoning. 

I had two children in tow when I arrived at Blenheim Palace this afternoon. Badger and two other birders were already watching it dip-feed at the back of the main lake. It was distant and the light was terrible. The Bonaparte’s Gull could be picked out from the many Black-headed Gulls just because it looked so clean and bright, an impression created by the pale inner primaries on the underwing. 

I  needed to tempt it closer. Feeling determined, I took my children up back into the main house and into the cafe. I didn’t buy them anything, but instead found myself wondering what the Bonaparte’s Gull would prefer: scones or sausage rolls? Despite the fact my wife does not eat pork and that a well known vegan Oxonbirder was looking after my ‘scope by the lakeside, I went for the meat. It worked a treat.

Black-headed Gulls noticed me tossing food into the air and came over to investigate. The Bonaparte’s came with them. It’s dark head – not really black, but darker than the accompanying Black-headed Gulls – was not quite complete: 

The leg colour was visible at quite some distance:

I even had the satisfaction of seeing the Bonaparte’s Gull, take a piece of my sausage roll:

Although this made it a target for other gulls…

…causing the Bonaparte’s Gull to react furiously:

Within a couple of minutes the food was gone and all the gulls returned to patrolling the far side of the lake. I took my children back to the cafe, to reward them for their patience, and we spent the rest of the afternoon enjoying the sunshine at Blenheim. Easy birding. 

 

The wonder of antennae

I am participating in the Garden Moth Scheme this year, so put out the moth trap in our garden every Friday evening and record our catch. This Friday saw a large increase in the number of moths and our first Oak Beauty:

The antennae on this moth are fabulous, especially the white dots running  along the shaft of the upper surface of the antennae:

This got me wondering.  Why do some moths have complex antennae, but most do not? Most moths have simple antennae. I was immediately encouraged to look into this. Partly because I have enjoyed photographing the amazing variations of antennae in our moth trap, but also because I have discovered that time stops when you start looking closely at moths. 

A number of different antennae shapes have been recorded in moths (image © here):

The majority of moths have simple antennae, like the Buff-tip, Poplar Hawk Moth and Brimstone Moths, below:

Others have fantastic pectinate or bi-pectinate antennae arrangements, resulting in some truly fabulous headgear. Below, Dark Arches, male Muslin Moth and Pale Prominent: 

Antennae have that evolved over time to perform a wide range of complex functions. These not only include detecting members of the opposite sex through picking up traces of their pheromones, but antennae also have a role to play in providing flight stability. However, in evolutionary terms, antennae began their life as something much more simple: once they were legs. 

The trochanter on the image above of an insect leg (© here), is at the junction between the body and the leg. In antennae this area has specialised to contain two wonderfully named organs: the Johnston’s Organ and the Böhm’s Bristles: 

Johnston’s Organ (in the pedicle or second section of the antennae) detects motion in flagellum (the third and final section of the antennae) and helps provide flight stability. It is tuned to detect angular changes during maneuvering in complex flight, as demonstrated in Hawkmoths here. 

Böhm’s Bristles appear to help control position of the antennae during flight. They are found at the base of the antenna and are tiny, but are visible in these images, labelled “BB” (© here):

The discovery that antennae help provide flight stability in moths is relatively new. Moth antennae are best known as organs of smell. They are highly specialised olfactory organs and can be incredibly sensitive. Amazingly, Indian Lunar Moths have been shown to be able detect a single sex pheromone molecule at a distance of 11km (6.5 miles), see here.

But if that is the case, then why do the majority of moths have simple filamentous antennae and only a minority a more complex array of antennae, like this Brindled Beauty, below?

Surely it would be an advantage to have the largest, most sensitive antennae possible? It appears that this would be the case, but there is a price to pay for having a huge array of pheromone detectors on your head. That price is flight efficiency. Complex bi-pectinate antennae are found on larger moths. Smaller, lighter moths cannot carry around complex antennae without compromising their flight efficiency. Larger moths are less abundant than smaller moths. This is why most moth species have simple filamentous antennae. 

Digging deeper, it appears that even simple filamentous antennae have adapted to improve the efficiency of sex hormone detection. Simple filamentous antennae are covered in scales, which have a function in the detection of pheromones:

This paper found that the presence of these scales increased the amount of nanoparticles (like pheromones) around the antenna, and even filtered out microparticles (like dust), which further increased the efficiency of the antenna. In this way the simple filamentous antennae of smaller moths have become increasingly sensitive at detecting pheromones, without compromising flight efficiency.  

The greater the detail you discover about the natural world, the greater the wonder it generates. The fact that complex pectinate arrays can make antennae look like giant ears is pretty cool too:Pale Tussock 

Out, at last.

It has not been an easy couple of months. In early February I sustained a stress fracture to my hip during a long run. Very quickly I was unable to walk or even weight bear. X-ray and MRI scans confirmed the diagnosis and I spent the next four week on crutches, unable to work. Fortunately the small crack in my femur, just below the ball and socket joint of my hip, did not need surgery and I should make a full recovery. But I was trapped inside for most of February and March. To stave off madness I caught up with lots of computer based work, including writing a few bird related contributions to the Cumnor village magazine:

By Monday morning, I was able to attempt a slow limp around some parts of Dix Pit. It is not reasonable to expect to find something good on your first trip out in 2 months, although an early migrant of some sort would have been nice. Today, just being out in the sunshine was enough. A Water Rail called, Chiffchaffs were singing…

… and the first Peacock butterflies were feeding on the blackthorn flowers. All had a little more meaning, after my period of incarceration. 

My eBird list of species seen is here.

A cold morning in the city

Thursday dawned with pre-work trip into Oxford city to follow up a report from Adam Hartley of a Lesser Spotted Woodpecker in the University Parks. It was a bitterly cold morning, cold enough to freeze the lake in the park and for ice to form on the River Cherwell, above. 

It was still well below zero when I climbed the Rainbow Bridge, perhaps too cold to encourage a small woodpecker to drum. I spent the next 45 minutes checking riverside trees on both sides of the river and listening out for calls or drumming. I found a Great Spotted Woodpecker drumming and excavating a hole, but there was no sound nor sight of a Lesser Spotted Woodpecker. 

Much more obvious were the pair of Ring-necked Parakeets that have taken up residence in the line of trees on the other side of Rainbow Bridge, where the footpath heads north-east towards the end of Edgeway Road. 

With time running out and my fingers beginning to seize up in the cold,  I called into Christchurch College on my way to work:

A Black Redstart, a scarce bird in the county, has been wintering here. This morning it spent its time on the bare branches of the Virginia Creeper on the front of the college, below:

It was perfectly camouflaged, grey plumage against the grey of the branches and the full sun brought the temperature up nicely too. 

 It seems incredible that there is enough insectiverous life on the outside of an Oxford College to support a bird through the winter. But throughout the time I watched it fed constantly, dashing up to take spiders from under the student’s window-ledges, flashing the pale orange tail that gives it it’s name:

I quite enjoyed some city centre birding, especially with Oxford looking stunning on a clear winters morning.

Oxfordshire Birding Awards 2018

Saturday night saw the annual gathering of Oxfordshire birders, at Majliss Indian Restaurant in Abingdon: 

As usual, the event was superbly organised by Badger, who also asked if I would be happy to present the awards again. Despite this, it was a great evening, with good bunch of people, decent food and much beer and wine. It is always great to get the local birding community together and the awards – mostly tongue-in-cheek – are a nice way of thanking people for their efforts over the year. To get an award you have to attend the meal (a hint for those thinking of attending next year!). This year the winners were:

The final award of the evening was a Lifetime Achievement Award for Barry Hudson. Barry is the secretary of the Oxford Ornithological Society and in many ways is the public face of the OOS. As an ex-farmer he has the credentials to work and influence the farming community towards more environmentally sustainable farming methods. Barry’s work on local Tree Sparrow conservation is well known. I first met Barry when he contacted me about putting up nesting platforms for Hobby in Cuddesdon, see here. Always open, friendly and generous, Barry has made a real difference to wildlife conservation within Oxfordshire. As Barry said on Saturday night, we must keep fighting for wildlife, because wildlife itself has no voice. It is our species that will decide the fate and diversity of the various bird, mammal and insect species in Oxfordshire and in the wider countryside. We need more Barry Hudsons.

Great Northern Diver

Somehow I have not seen Great Northern Diver in Oxfordshire. Birds have often overwintered at Farmoor, in some years multiple birds. But all recent records were in my “Cuddesdon years”, when I was concentrating on my local patch, rather than county birding. Just before Christmas this year a juvenile Great Northern Diver was found on a small lake at Beale Park, just over the county border in Berkshire. In the first few days of January reports emerged that it was also feeding on the River Thames, just inside the county. Suddenly it got more interesting.

A quick look at a map revealed just how close to the border this bird was. The county boundary is the black dash-dot line that runs down the river:

The county boundary runs south on the right (east) side of the river until opposite Beale Park (“Wildlife Park” on the map above). Then, inexplicably, it crosses the river to run south, on the left (west) side of the Thames. The lake on which the Diver was first found is fed by a small stream that runs into the Thames at almost exactly the point that the county line crosses the river, just south of two small islands:

Below, Oxfordshire on the right, Berkshire in red, on the left:

So, for me to see this bird in Oxfordshire it needed to be on the River Thames, but south of the feeder stream from the lake in Beale Park. If it was on the lake, or on the River Thames north of the feeder stream, it was in the red zone, aka Berkshire, and was no use whatsoever for my county list. Having established the all important landmarks, I set out this morning to see where the bird was.

I walked up the tow path, passing a Little Grebe, a few Cormorants and lots of Siskins and found the juvenile Great Northern Diver on the river. It was reported to favour the area at the mouth of the feeder stream, but frustratingly, was north of this when I found it, so was in Berkshire. By about 8 meters. The views however, were superb:

It was diving frequently, but also spent some time just loafing, gently paddling against the northerly current, which kept it excruciatingly just outside of Oxfordshire. Surely, at some point it would just float over the invisible line and onto my Oxfordshire list?

It was a dark grey morning, with terrible light, but I took pictures of the bird as it surfaced between dives into the waters of Berkshire.

I was simultaneously enjoying being quite close to a Great Northern Diver and getting frustrated at its avoidance of my home county. Then, after about half an hour, a small group of rowers came up the river from the south. The Great Northern Diver took one look at them, dived deep and long and popped up behind them… in Oxfordshire!

Even more convincingly, it then spent some time well south of the feeder stream. I saw it as far south as the house on the east bank – a whole 250 meters inside the county! Tick.

Chiltern Mandarins

In the absence of time to do any proper birding, a family walk in the Chilterns (about 20km outside of Oxfordshire) produced some nice autumn colours today in the shape of a flock of Mandarin. A non-native species, but one of the better looking ones. Continuing the non-native theme, there were quite a few Ring-necked Parakeet in the woods too, both species seem to be working their way west towards Oxfordshire: 

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